改性二氧化钛纳米管研究

TiO2纳米管因其所具有的优异性能，使其在光催化、光解水制氢、太阳能电池等领域具有广阔的应用前景，尤其是对Ti02纳米管掺杂改性后，将会大大改善其性能。本文介绍各种改性TiO2纳米管的制备方法和性能，并对TiO2纳米管的进一步深入研究提出建议。     

钛箔表面二氧化钛纳米管的可控制备研究

采用电化学阳极氧化法在金属钛箔表面制得了二氧化钛纳米管,通过调整阳极氧化电压和时间,控制纳米管的管径及管壁尺寸,采用扫描电镜(SEM)观察了不同制备条件下得到TiO2纳米管阵列的微观形貌,考察了氧化电压及时间对纳米管TiO2纳米管阵列形貌的影响;利用热处理工艺调整二氧化钛纳米管的晶型,通过X射线衍射仪(XRD)对样品晶型进行了表征.结果 表明,以0.5％氟化铵的乙二醇水溶液作为电解液,在40 V电压下氧化30 min,得到的TiO2纳米管整齐有序;经过450℃热处理2h,TiO2纳米管晶型由无定型态转变为锐钛矿型TiO2,纳米管出现小部分坍塌.     

四脚状CdSe敏化TiO2纳米管阵列薄膜光电性能研究

采用阳极氧化法在钛基底上生长了一维高度有序TiO2纳米管阵列,并与CdSe四脚状晶体及CdSe量子点组装成一种新型的量子点敏化太阳能电池( QDSSCs).该阵列结构为光生电子的传递提供了快速通道,CdSe四脚状三维空间结构增加了其吸附在TiO2纳米管阵列的稳定性.采用XRD,SEM和HR-TEM对阵列及CdSe四脚状和量子点进行了表征.考察了CdSe四脚状和量子点敏化纳米管阵列三电极电池结构的光电性能.XRD谱图表明TiO2的锐钛矿晶型特征峰没有发生变化,同时出现了一系列的CdSe六方晶型和立方晶型特征峰.SEM图表明所制备的TiO2具有高度有序的纳米管阵列结构,且孔径大小均一、约为120 nm,长度近13.8 μm.TEM和HRTEM图表明CdSe量子点具有四脚结构,CdSe核的直径约为4.1nm,臂宽约为3.1nm,臂长约为16.0nm.结果表明:通过四脚状CdSe修饰TiO2纳米管阵列基电极在可见光谱区域的吸收得到了明显增强;此外,在模拟太阳光(AM 1.5 100 mW·cm-2)的照射下,四脚状CdSe敏化比CdSe量子点敏化TiO2纳米管阵列三电极结构电池的光电转换效率高,它们分别为0.13％和0.30％.     

TiO2光电催化制氢基本原理及其影响因素

概述TiO2半导体光电催化分解水制氢基本原理，着重介绍平带电位的影响和TiO2薄膜的性能，并概括了施加外加偏置电压的方法；概述了常见的半导体修饰方法的基本原理。最后指出光电催化制氢尚待解决的一些基本问题并展望了光电催化制氢的应用前景。     

TiO2纳米管的制备及其光催化降解甲基橙的研究

以TiO2和NaOH为原料,采用水热法制备了TiO2纳米管（titania nanotube,简称TNT）,通过X射线衍射（XRD）、扫描电子显微镜（SEM）对TiO2纳米管的结构与形貌进行了研究,以甲基橙（Methyl Orange）为反应物,考察了TiO2纳米管光催化降解甲基橙的效果。研究结果表明：400℃焙烧时,TiO2纳米管主晶相为钛酸,500℃焙烧时,其组成为锐钛矿相;制备的TiO2纳米管可以有效的降解甲基橙,且在光催化降解中起主要作用的是锐钛矿相。     

双通TiO2纳米管阵列光催化膜的研制

采用阳极氧化法,在钛箔上制备TiO2纳米管阵列,并利用HF气体去处其阻挡层,并作了SEM,Uv-Vis表征,表明获得了具有光催化性能的双通TiO2纳米管阵列.以双通TiO2纳米管阵列为光催化剂,在紫外光照射下进行甲基橙的降解实验,2 h内甲基橙降解率可以达到86%(A=484 nm),发现其光催化降解甲基橙的效果明显较好.     

TiO2纳米管阵列涂层的相态和形貌对其光催化活性的影响研究

通过阳极氧化法在金属钛表面制备了TiO2纳米管阵列涂层(TiO2 nanotube array,TNT),并通过改变其形貌和相态探索TNT涂层光催化反应的机理。研究表明TNT涂层光催化降解有机物的机理是依靠光生空穴与氧化剂生成的羟基自由基来氧化有机物中的基团。此外涂层表面的F离子残留量对TNT涂层的光催化性能有一定的影响,F离子残留量越少,纳米管的光催化活性越高,这是由于在光照条件下,带有负电的F离子易于和带正电的光生空穴发生反应,同时由于F离子的残留使纳米管中出现了Ti3+,从而降低了光生电子的数量。低温退火处理条件下,纳米管的形貌基本上没有改变,影响半导体材料性能的主因是相态变化,锐钛矿占主体的混晶结构能够有效促进光生电子-空穴对的分离和传输,从而提高光催化性能。     

氧化镧掺杂TiO2纳米管的制备及光催化性能研究

用水热合成法制备了掺镧的TiO2纳米管。以甲基橙作为脱色对象,对掺镧TiO2纳米管、掺镧TiO2纳米粉末、TiO2纳米管的光催化进行现象对比研究,其中掺镧的TiO2纳米管催化活性最高,以TEM、XRD、BET等分析手段对其进行了表征,并对结果进行了分析与讨论。     

TiO2纳米管的制备及其在太阳能电池中的应用

TiO2纳米管具有大的比表面积和较强的电子传输能力等特点,同时由于具有强的光散射特性,当应用到太阳电池光阳极材料中,能提高光虏获能力,因此在太阳能电池材料中具有较大的发展潜力.采用阳极氧化法可制备具有高度垂直于衬底且可控性高的TiO2纳米管.论述了TiO2纳米管的制备工艺及其在光伏电池,特别是在染料、量子点敏化太阳能电...     

Ru负载TiO_2纳米管阵列的制备及其光电催化性能

结合阳极氧化法和脉冲沉积法合成了管径约40～70 nm、管壁厚约10 nm、管长约1μm、管壁上附着Ru纳米颗粒的TiO_2纳米管光催化剂(Ru/TiO_2),实现了金属Ru纳米颗粒在TiO_2纳米管表面的均匀负载。研究了RuCl_3浓度和煅烧温度对TiO_2纳米管的微观结构、光吸收特性及光催化活性的影响。结果表明:Ru的负载使Ru/TiO_2纳米管的光学带隙值有所减小,光响应阈值发生红移;锐钛矿相TiO_2与少量金红石相TiO_2可形成异质结,纳米Ru可俘获光生电子,两者都可促进光生电子-空穴对的分离,从而提升降解效率;另外,外加偏压也可促进光生电子-空穴对的分离,从而进一步提升降解效率。当脉冲沉积液中RuCl_3浓度为0. 05 mol·L~(-1),经600℃煅烧后的Ru/TiO_2纳米管阵列的光催化活性最好,对甲基橙降解1 h,紫外光下的光催化和光电催化分解比例由纯TiO_2纳米管的38. 6%和48. 5%提升至52. 0%和70. 5%,可见光下的光催化和光电催化分解比例由纯TiO_2纳米管的7. 1%和17. 2%提升至36. 3%和75. 2%。     

Gd3+掺杂纳米TiO2的制备及性能

采用溶胶-凝胶浸渍法制备了纯的和Gd3+掺杂的纳米TiO2,并利用XRD、UV-Vis漫反射光谱对样品进行了表征。考察了Gd3+掺杂对TiO2催化活性的影响。结果发现Gd3+的掺入阻止了TiO2由锐钛矿相向金红石相的转变,抑制了晶粒的生长。与纯TiO2相比,Gd3+掺杂的TiO2在紫外区的光吸收能力增强,TiO2催化剂光催化分解水制氢活性提高了56%。     

Hydrogen effects in [001] oriented nickel-base superalloy single crystals

The entry and subsequent interaction of hydrogen on the mechanical properties of the single crystal nickel-base super alloy CMSX-2 has been studied. Significant amounts of hydrogen were introduced by high temperature hydrogen charging in molten salts which led to an increased lattice parameter and microhardness and to a degradation in tensile elongation to failure whose extent scales with the depth of the hydrogenated zone. In this region a fracture mode change from a {111} to a {100} type also occurred. The values of the binding energy of hydrogen to solidification voids and the effective hydrogen pressure in the voids were estimate.     

[w(TiO2)]对烧结矿矿相结构及软熔滴落性能的影响

 为了深入研究[w(TiO2)]对烧结矿冶金性能的影响,通过SEM-EDS和荷重软化熔滴试验研究了不同TiO2质量分数对烧结矿矿相结构与软熔滴落性能影响。试验结果表明,随着烧结料中[w(TiO2)]从1.40%增加到3.02%,烧结过程液相生成量先增加后减少,烧结矿中的赤铁矿、钙钛矿和硅酸盐等都有不同程度的升高,赤铁矿质量分数从20.69%增加到26.05%,其形态由原生赤铁矿逐步变为二次赤铁矿,磁铁矿和复合铁酸钙质量分数逐步减少,因此,适当增加烧结矿中[w(TiO2)]（＜2%）有利于改善烧结矿的液相生成量,减少燃料消耗,提高烧结矿的转鼓强度;烧结矿中的钛主要以钙钛矿的形式存在,极少部分的钛固溶于复合铁酸钙和二次赤铁矿中;随着烧结矿中TiO2质量分数的增加,开始软化温度逐渐升高,试样软化开始温度[t10]和试样软化终了温度[t40]均在1 130 ℃以上,低钛烧结矿的软化温度区间[ΔtA]为195 ℃,其余含钛烧结矿烧结矿的软化温度区间[ΔtA]均在200 ℃以上。     

CdS/Eu~(3+)-TiO_2复合光催化剂制备及性能研究

用溶胶-凝胶法制备了复合光催化剂CdS/TiO2和CdS/Eu3+-TiO2。利用XRD、UV-Vis漫反射光谱对样品进行了表征。以可见光分解水制氢为探针反应考察了催化剂的活性。结果发现Eu3+掺杂TiO2后抑制了TiO2晶粒生长,提高了光生电子和空穴的分离,从而提高了复合光催化剂的活性。     

Preparation and Methanol Decomposition Activity of RutheniumSupported Ce-Doped Mesoporous TiO_2 Oxide

Mesoporousmaterials ,forexamplesilicicMCM 4 1,havebeenoftenemployedasacatalystsupportandshowedsignificantcatalyticactivity ,becausetheactivemetalscanbehighlydispersedinthecharacter isticporestructurewithhighsurfacearea[1] .Titaniaseemstobeanactivesupport …     

No-carrier-added synthesis of meta-[131I]iodobenzylguanidine

No-carrier-added meta-[131I]iodobenzylguanidine ([131I]MIBG) was prepared starting with two different metallated precursors. Attempted preparation of 3-(tri-n-butylstannyl)benzylguanidine was not successful. An alternate two-step strategy using 3-(tri-n-butylstannyl)benzylamine could be used to prepare radio-iodinated [131I]MIBG in an overall radiochemical yield of 30-33%. Synthesis of [131I]MIBG via the radioiododesilylation of 3-trimethylsilylbenzylguanidine was also investigated. Yields were dependent on temperature, precursor concentration, solvent and nature of the oxidant. Radiochemical yields of 90% were obtained in 5 min at room temperature using either N-chlorosuccinimide or hydrogen peroxide in trifluoroacetic acid as oxidants. The percentage of specific binding in vitro of no-carrier-added MIBG to SK-N-SH neuroblastoma cells remained constant over a 2 log activity range, while the binding of MIBG prepared by isotopic exchange dropped by a factor of seven. In normal mice, heart and adrenal uptake of no-carrier-added [131I]MIBG was found to be higher than that of [131I]MIBG prepared by isotopic exchange.     

Synthesis and Characterization of Monetite Prepared Using a Sonochemical Method in a Mixed Solvent System of Water/Ethylene Glycol/N,N-Dimethylformamide

Bioactive monetite (anhydrous calcium hydrogen phosphate, CaHPO₄) has been successfully synthesized using the sonochemical method in the presence of a ternary solvent system of water/ethylene glycol (EG)/N,N-dimethylformamide (DMF). The morphology and chemical composition of the synthesized powders were characterized using field emission scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The results indicated that with increasing sonication time, the morphology changed slightly from a plate-like one to a combination of plates (flower-like). The formation of flower-like nanosheets requires an optimum time of 40 minutes, and the nanosheets have an average thickness of 210 ± 87 nm. The concentration of DMF clearly influences the morphology and crystal phase of the products. The ideal product was obtained using a water/EG DMF ratio of 1:2.     

Epitope specificities and antibody responses to the EG95 hydatid vaccine

Antibody isotype and epitope specificities were examined in sheep immunized with EG95, a protective recombinant vaccine against hydatid disease. All sheep immunized with EG95 as a fusion protein with glutathione S-transferase (GST) produced prominent IgG antibodies against the EG95 portion of the protein. Linear, antibody-binding epitope specificities of EG95 were mapped using a series of 25 overlapping synthetic peptides. Three immunodominant regions were identified which generated specific IgG1 and IgG2 antibodies in the majority of vaccinated sheep. These regions corresponded to the EG95-derived sequences SLKAVNPSDPLVYKRQTAKF, DIETPRAGKKESTVMTSGSA and SALTSAIAGFVFSC. An additional immunogenic region was identified which induced almost exclusively IgG2 antibody. This epitope was located within the sequence TETPLRKHFNLTPV. The anti-parasitic, protective effects of the EG95 vaccine correlated with the detection of specific antibody to two or more of the four linear immunogenic regions. The identification of these immunogenic peptides of EG95 maybe useful in the development of a synthetic peptide vaccine as a derivative of the EG95 recombinant.     

稀土改性Ni/TiO_2光催化剂及其重复利用催化活性

用溶胶-凝胶法制备了La或Ce改性的0.3%Ni/TiO2(即La-Ni/TiO2或Ce-Ni/TiO2),考察了La-Ni/TiO2或Ce-Ni/TiO2在催化降解甲基橙水溶液过程中的重复利用性能,并用XRD、N2吸附-脱附以及XPS等手段对催化剂进行了表征分析。研究表明,适宜La和Ce掺杂量(La/Ti、Ce/Ti摩尔比)分别为0.15%和0.1%,适宜焙烧温度为400℃。在酸性条件下(pH=3),La-Ni/TiO2和Ce-Ni/TiO2与Ni/TiO2光降解甲基橙的能力相当,但La或Ce掺杂使Ni/TiO2催化剂的重复使用能力提高。催化剂上存在低结合能的低价钛离子(如Ti3+),低价钛离子的含量和结合能大小是衡量催化剂光催化降解活性的重要因素。可能是La或Ce使催化剂在使用过程中低价钛离子得到较好保留,从而使催化剂活性得到较好维持,催化剂重复使用性能提高。